The Nautilus E452 survival suit is made by Helly Hansen Canada Ltd. (Helly Hansen)

A bright orange garment with water-sensitive beacons, the survival suit is designed to give victims those precious extra hours needed for rescue crews to find them.

When a Sikorsky S-92 helicopter ditched in the Atlantic off the coast of Newfoundland Thursday with 18 passengers aboard, all would have been wearing Nautilus E452 suits, made by Helly Hansen.

Such suits are typically sold to oil and gas companies doing exploration work over water, but are also used by the coast guard, military and navy.

The Nautilus suit is outfitted with an inflatable life-jacket that immediately activates in water, said Shawn Amirault, vice-president of sales and marketing for Helly Hansen Canada Ltd.

Other suit features include a breathing system to supply air to the person in emergencies.

The Nautilus suit is also equipped with a personal locator beacon that activates within 20 seconds of hitting water so rescue crews can quickly home in on the victim's location in the wide expanse of ocean, said Amirault. Though some beacons are equipped with GPS, these were not.

In the case of the Sikorsky S-92 helicopter, search and rescue crews reported that no signals were received from the beacons of the 16 missing passengers. One man was pulled alive from the ocean and one body has been recovered.

Experts surmise that the absence of any signals may indicate the suits were submerged deep under water.

"It certainly could be depth. It's troubling that there are 16 individuals missing and we haven't heard from a single one of them. So that's one of the … nagging issues out there with the rescue operation right now," said Stephen Cheung, an expert in hypothermia from Brock University, in St. Catharines, Ont.

Cold, heat both pose risks

Cheung, who has trained to survive a ditched helicopter, says it can be "catastrophic" if the seal on the suits break, allowing any water to get in.

That eliminates the suit's ability to keep a person dry, enabling a healthy person in their 30s to survive 24 hours in near freezing water.

"The whole purpose of this is to have an air layer between you and the outside water to keep you as dry and as warm as possible," said Cheung.

Once your body is in contact with water, the water begins conducting heat away from your skin and puts you at risk of hypothermia.

As muscles start shivering to try to stay warm, it becomes increasingly difficult to move your limbs to try to open a flare or even get into a life-raft, said Cheung.

Water leaks also decrease the buoyancy of the suit, which can weigh 15 to 20 pounds.

Although the suit is designed to be impenetrable, helicopter passengers can put themselves at risk by opening it.

Helicopters can heat up quickly in the sun, causing some passengers to unzip their body suits during the ride.

"It's a natural temptation.… It is like a big fish bowl with the sun blaring in the helicopter, lots of glass. And it can be very, very hot in there," said Cheung.

Cheung is currently working on a project looking at whether heat stress from wearing survival suits can also impair reaction during emergency situations.